What can you tell me about the shimmy damper used on our planes? Are they repairable, or must they be replaced? Are there any alternatives?
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Technical Editor:
The original 1963 shimmy damper was the same Lord unit used on the Bonanza and Baron nose gears. With the trailing link design, and the mass inherent in the heavy Musketeer nose gear and tire, the Lord unit couldn’t do the job when the nose gear began to loosen up. This issue arose during the 1962 nationwide sales demonstration flights made by ‘The Three Musketeers’, memorialized in the book by that name, written by Gene Nora Jessen (get it and read it!).
Beech switched to a sealed damper that was nothing more than a slightly downsized bi-directional automotive shock absorber, made by Monroe Corporation. The sealed damper is non-repairable. They were, however, of excellent quality. At least half of the originals, if not more, remain in service today, despite being in service for 35 or more years.
The sealed dampers were replaced by a series of repairable units. Here is all of the parts information for all of the shimmy dampers used on the 19/23/24/76/77 airframes:
169-380029 Nose gear sealed shimmy damper assembly. Superseding part numbers have suffixes of -1, -3, -5, and -7; the most recent being the 169-380029-7. The -7 is contained in adapter kit PN 23-8010-1 S, though the kit is both exorbitantly priced and unavailable.
C100016-1B Shimmy damper repair kit, for the -3, -5, and -7 repairable (non-sealed) dampers. The manufacturer’s part number is H-6B72. There is no known source for these kits. The kit contents include:
MS28775-117 retaining cap seal (shaft end); standard o-ring
MS28775-210 piston OD seal; standard o-ring
B1015A shaft seal (no known source)
B100151 shaft assembly (no known source)
HF6G Nose gear shimmy damper rod end (readily available from parts suppliers)
The following shimmy dampers are essentially standard Beech Model 35 dampers used on Bonanzas and Barons. They are also used on the Duchess and Skipper as shown, with some minor differences.
35-825145 Duchess shimmy damper (Baron nose gear). This unit contains:
2ea MS83461-6 Shimmy damper floating piston O-ring, originally AN6227-1 or MS28775-006
2ea MS83461-12 Shimmy damper end cap shaft O-ring, originally AN6227-7 or MS28775-012
4ea MS83461-113 Shimmy damper end cap sealing O-ring, originally AN6227-13 or MS28775-113
108-320035-1 Skipper shimmy damper. This variant of the Bonanza damper uses the Bonanza housing, but has a different piston assembly (different shaft and different piston). It contains the following parts:
2ea MS83461-12 Shimmy damper shaft O-ring, originally AN6227-7 or MS28775-012
2ea MS83461-115 Shimmy damper cap O-ring, originally AN6227-13 or MS28775-115
This link will take you to the shimmy damper repair kit instruction document available on BAC (Technical/Downloads/Articles):
https://www.beechaeroclub.org/modules/UpDownload/store_folder/Articles,_Reference_Documents/C-10016-1B_Damper_Repair_Kit.pdf